CVE-2026-43378

Description

In the Linux kernel, the following vulnerability has been resolved: smb: server: fix use-after-free in smb2_open() The opinfo pointer obtained via rcu_dereference(fp->f_opinfo) is dereferenced after rcu_read_unlock(), creating a use-after-free window.

Overview

State: PUBLISHED
Assigner (CNA): Linux
CVSS severity: high
CVSS score: 7.8 / 10
CVSS vector: AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Effective score: 7.8 / 10 HIGH source: CNA overview
CWE(s): —
Reserved: 2026-05-01
Published: 2026-05-08 16:21 UTC
Last updated: 2026-05-12 00:23 UTC
Source: https://raw.githubusercontent.com/CVEProject/cvelistV5/main/cves/2026/43xxx/CVE-2026-43378.json
Linked Threat: CVE-2026-43378 — CVE-2026-43378

NVD triage scoring NVD CVE 2.0

Layer NVD adds on top of the CNA's CVE record — published / last-modified timestamps, exploitability / impact subscores, and the FIRST.org EPSS probability that this CVE will be exploited in the wild in the next 30 days.

NVD published: 2026-05-08 15:16:48 UTC
NVD last modified: 2026-05-20 17:16:22 UTC
NVD CVSS v3.1: 9.8 / 10 CRITICAL source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
NVD CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Exploitability subscore: 3.9 / 10
Impact subscore: 5.9 / 10
EPSS score: 0.0003 (probability of exploitation in next 30 days)
EPSS percentile: 8.22% vs all CVEs — higher = more likely to be exploited, as of 2026-05-24

NVD-assigned CWE(s): CWE-416 (differs from the CNA list above)

European Union Vulnerability Database ENISA EUVD

ENISA's official EU repository for curated vulnerability intelligence. Carries a separate identifier (EUVD-YYYY-NNNN) and frequently exposes an earlier-published description + CVSS than NVD does.

EUVD ID: EUVD-2026-28684
Assigner: Linux
Published: May 8, 2026, 2:21:27 PM
Updated: May 20, 2026, 4:08:05 PM
EUVD base score (CVSS 3.1): 9.8 / 10
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EUVD-reported EPSS: 0.0300
Vendors: Linux
Products: Linux (e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 <54b48ae83de8bb06e65079d96368efe359d4909c)

Linux (e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 <8f5b1a7cb009a93c48e9e334a2f59a660f9afc07)

Linux (patch: 0)

Linux (patch: 6.19.9)

Linux (patch: 6.1.167)

Linux (e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 <190e5f808e8058640b408ccfed25440b441a718a)

Linux (patch: 6.6.130)

Linux (1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <54b48ae83de8bb06e65079d96368efe359d4909c)

Linux (e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 <b720c84087cb547f23ce03eab93568c1769e4556)

Linux (e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 <e1b21e6066615e7d3d3a7aa2677e415e563fd7cc)

Linux (1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <190e5f808e8058640b408ccfed25440b441a718a)

Linux (1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <e1b21e6066615e7d3d3a7aa2677e415e563fd7cc)

Linux (e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 <1e689a56173827669a35da7cb2a3c78ed5c53680)

Linux (1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <8f5b1a7cb009a93c48e9e334a2f59a660f9afc07)

Linux (1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <1e689a56173827669a35da7cb2a3c78ed5c53680)

Linux (patch: 7.0)

Linux (patch: 6.12.78)

Linux (1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <b720c84087cb547f23ce03eab93568c1769e4556)

Linux (patch: 6.18.19)

Linux (5.15)

ENISA description: In the Linux kernel, the following vulnerability has been resolved: smb: server: fix use-after-free in smb2_open() The opinfo pointer obtained via rcu_dereference(fp->f_opinfo) is dereferenced after rcu_read_unlock(), creating a use-after-free window.

EUVD references (6)

Affected products (2)

Vendor	Product	Versions	Platforms
Linux	Linux	`e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9` (affected), `e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9` (affected), `e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9` (affected), `e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9` (affected), `e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9` (affected), `e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9` (affected)	—
Linux	Linux	`5.15` (affected), `0` (unaffected), `6.1.167` (unaffected), `6.6.130` (unaffected), `6.12.78` (unaffected), `6.18.19` (unaffected), `6.19.9` (unaffected), `7.0` (unaffected)	—

Affected products — CPE 2.3 (4) NVD

NVD's normalized CPE 2.3 matchers, used by vendor tools (vulnerability scanners, asset managers) for automated detection. Compare with the CNA's free-text "Affected products" section above.

cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:7.0:rc1:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:7.0:rc2:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:7.0:rc3:*:*:*:*:*:*

Vendor references (6)

References embedded in the original CVE record by the assigning CNA.

MITRE references (6) cveawg.mitre.org

Pulled from MITRE's CVE Services API by the 🛰 Backfill from MITRE button.

Web references (6)

DuckDuckGo results ranked by threat-intel / vendor advisory domains. Generated by the 🔎 Find references (web) button above — same flow as the Remediations search.

http://cwe.mitre.org/data/definitions/416.html rapid7:cwe.mitre.org
https://attackerkb.com/topics/CVE-2026-43378 rapid7:attackerkb.com
https://euvd.enisa.europa.eu/vulnerability/EUVD-2026-28684 rapid7:euvd.enisa.europa.eu
https://www.first.org/epss/ tenable:www.first.org
https://nvd.nist.gov/vuln/detail/CVE-2026-43378 tenable:nvd.nist.gov
https://www.cve.org/CVERecord?id=CVE-2026-43378 tenable:www.cve.org

NVD-tagged references (6)

Reference list NVD curates from the CNA record, vendor advisories, and third-party reports. The tag chips below are NVD's analyst-assigned categories.

https://git.kernel.org/stable/c/190e5f808e8058640b408ccfed25440b441a718a 416baaa9-dc9f-4396-8d5f-8c081fb06d67 Patch
https://git.kernel.org/stable/c/1e689a56173827669a35da7cb2a3c78ed5c53680 416baaa9-dc9f-4396-8d5f-8c081fb06d67 Patch
https://git.kernel.org/stable/c/54b48ae83de8bb06e65079d96368efe359d4909c 416baaa9-dc9f-4396-8d5f-8c081fb06d67 Patch
https://git.kernel.org/stable/c/8f5b1a7cb009a93c48e9e334a2f59a660f9afc07 416baaa9-dc9f-4396-8d5f-8c081fb06d67 Patch
https://git.kernel.org/stable/c/b720c84087cb547f23ce03eab93568c1769e4556 416baaa9-dc9f-4396-8d5f-8c081fb06d67 Patch
https://git.kernel.org/stable/c/e1b21e6066615e7d3d3a7aa2677e415e563fd7cc 416baaa9-dc9f-4396-8d5f-8c081fb06d67 Patch

Remediations (17)

Remediations are stored against the linked Threat row; the list below is deduplicated across both pages.

Oracle Critical Patch Update (CPU) April 2026 for Oracle Java SE

web:docs.oracle.com

Oracle Critical Patch Update (CPU) April 2026 for Oracle Java SE Services: Java Management Release Date: April 21, 2026

2026-05-23 21:05 UTC
Patch Tuesday, May 2026 Edition - Krebs on Security

web:krebsonsecurity.com

Microsoft expects that exploitation is more likely. May's Patch Tuesday is a welcome respite from April, which saw Microsoft fix a near-record 167 security flaws.

2026-05-23 21:05 UTC
Security Update Guide - Microsoft

web:portal.msrc.microsoft.com

The Security Update Guide provides information on the latest Microsoft security updates, helping users understand and address potential vulnerabilities effectively.

2026-05-23 21:05 UTC
CVE-2026-43500 and CVE-2026-43284 analysis

web:socprime.com

Explore Detections CVE - 2026 -43500 and CVE - 2026 -43284 Mitigation Practical CVE - 2026 -43500 mitigation starts with reducing available attack paths before a vendor patch is fully available across environments.

2026-05-23 21:05 UTC
SAP Security Patch Day - February 2026

web:support.sap.com

SAP security Patch Day Bulletin

2026-05-23 21:05 UTC
April 2026 Patch Tuesday: Updates and Analysis | CrowdStrike

web:www.crowdstrike.com

Microsoft's April 2026 Patch Tuesday addresses 164 CVEs , featuring 8 Critical vulnerabilities, one exploited zero-day, and one disclosed zero-day.

2026-05-23 21:05 UTC
Vulnerability Remediation vs. Mitigation: What are the Differences ...

web:www.secure.com

Learn the difference between vulnerability remediation and mitigation , and how a risk-based strategy can strengthen your security posture.

2026-05-23 21:05 UTC
CVE-2026-44338: PraisonAI authentication bypass in under 4 hours and ...

web:www.sysdig.com

CVE - 2026 -44338 in PraisonAI was exploited in under 4 hours, highlighting the growing trend of rapid CVE weaponization and AI-driven attacks.

2026-05-23 21:05 UTC
Windows 11 April 2026 Update tested: What's new, improved and fixed

web:www.windowslatest.com

Windows 11 April 2026 update adds Narrator Copilot support, faster Settings, File Explorer fixes, and key security improvements.

2026-05-23 21:05 UTC
Patch Tuesday May 2026: Security Updates & CVE Analysis

web:zecurit.com

Get the complete breakdown of Microsoft's May 2026 Patch Tuesday. We analyze the latest security updates and all critical CVEs .

2026-05-23 21:05 UTC
Windows Kerberos RC4 deprecation: what will break in Active ... - 4sysops

web:4sysops.com

Starting in April 2026 , Windows updates will change the default Kerberos ticket issuance behavior to AES-SHA1 for accounts without explicit encryption settings, while RC4 can still be used where explicitly enabled. This change, driven by CVE - 2026 -20833, affects every Windows Server environment where service accounts or devices still rely on RC4. Any service account, NAS device, or legacy ...

2026-05-26 02:47 UTC
Microsoft and Adobe Patch Tuesday, April 2026 Security Update Review

web:blog.qualys.com

With Qualys Policy Audit's out-of-the-box mitigation or Compensatory Controls, which reduce the risk of a vulnerability being exploited because the remediation ( fix / patch ) cannot be done immediately, these security controls are not recommended by any industry standards, such as CIS and DISA-STIG.

2026-05-26 02:47 UTC
Security Advisory Bulletin 064 | Ubiquiti Community

web:community.ui.com

Published: May 21, 2026 Updated: May 22, 2026 Version: 1.1 Revision: 1.1 Summary 1 of 5 A malicious actor with access to the network and high privileges could exploit an Improper Input Validation vulnerability found in UniFi OS devices to execute a Command Injection. Affected Products: UniFi OS Server (Version 5.0.6 and earlier) Mitigation : Update your UniFi OS Server to Version 5.0.8 or later ...

2026-05-26 02:47 UTC
CISA Warns of Exploited Microsoft Defender 0-Day Flaws

web:cyberpress.org

The U.S. Cybersecurity and Infrastructure Security Agency (CISA) has added two actively exploited Microsoft Defender vulnerabilities to its Known Exploited Vulnerabilities (KEV) catalog, issuing an urgent remediation directive for federal agencies with a due date of June 3, 2026 .

2026-05-26 02:47 UTC
Landing Page | ServiceNow Common Vulnerabilities & Exposures (CVE ...

web:support.servicenow.com

Overview The advisories below document publicly disclosed Common Vulnerabilities and Exposures ( CVEs ) in the Now Platform by ServiceNow. Because ServiceNow uses various methods to communicate vulnerability information, patches, and other fixes, customers should review family, security patch , and hotfix release notes, which are available at https://docs.servicenow.com, for a complete list of ...

2026-05-26 02:47 UTC
Microsoft Technical Security Notifications

web:www.microsoft.com

Security Update Guide Notifications Microsoft's free Security Update Guide Notifications provide links to security-related software updates and notification of re-released security updates. These notifications are sent via email throughout the month as needed.

2026-05-26 02:47 UTC
Oracle Critical Patch Update Advisory - April 2026

web:www.oracle.com

This Critical Patch Update contains 481 new security patches across the product families listed below. Please note that an MOS note summarizing the content of this Critical Patch Update and other Oracle Software Security Assurance activities is located at April 2026 Critical Patch Update: Executive Summary and Analysis.

2026-05-26 02:47 UTC

AI Forensic Analysis

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Raw JSON

The full cvelistV5 record. Download as CVE-2026-43378.json.

{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/smb/server/smb2pdu.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "e1b21e6066615e7d3d3a7aa2677e415e563fd7cc",
              "status": "affected",
              "version": "e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9",
              "versionType": "git"
            },
            {
              "lessThan": "b720c84087cb547f23ce03eab93568c1769e4556",
              "status": "affected",
              "version": "e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9",
              "versionType": "git"
            },
            {
              "lessThan": "54b48ae83de8bb06e65079d96368efe359d4909c",
              "status": "affected",
              "version": "e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9",
              "versionType": "git"
            },
            {
              "lessThan": "8f5b1a7cb009a93c48e9e334a2f59a660f9afc07",
              "status": "affected",
              "version": "e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9",
              "versionType": "git"
            },
            {
              "lessThan": "190e5f808e8058640b408ccfed25440b441a718a",
              "status": "affected",
              "version": "e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9",
              "versionType": "git"
            },
            {
              "lessThan": "1e689a56173827669a35da7cb2a3c78ed5c53680",
              "status": "affected",
              "version": "e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "fs/smb/server/smb2pdu.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.15"
            },
            {
              "lessThan": "5.15",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.167",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.130",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.78",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.19",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.19.*",
              "status": "unaffected",
              "version": "6.19.9",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.0",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.1.167",
                  "versionStartIncluding": "5.15",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.6.130",
                  "versionStartIncluding": "5.15",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.78",
                  "versionStartIncluding": "5.15",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.19",
                  "versionStartIncluding": "5.15",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.19.9",
                  "versionStartIncluding": "5.15",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.0",
                  "versionStartIncluding": "5.15",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nsmb: server: fix use-after-free in smb2_open()\n\nThe opinfo pointer obtained via rcu_dereference(fp->f_opinfo) is\ndereferenced after rcu_read_unlock(), creating a use-after-free\nwindow."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-05-11T22:23:25.827Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/e1b21e6066615e7d3d3a7aa2677e415e563fd7cc"
        },
        {
          "url": "https://git.kernel.org/stable/c/b720c84087cb547f23ce03eab93568c1769e4556"
        },
        {
          "url": "https://git.kernel.org/stable/c/54b48ae83de8bb06e65079d96368efe359d4909c"
        },
        {
          "url": "https://git.kernel.org/stable/c/8f5b1a7cb009a93c48e9e334a2f59a660f9afc07"
        },
        {
          "url": "https://git.kernel.org/stable/c/190e5f808e8058640b408ccfed25440b441a718a"
        },
        {
          "url": "https://git.kernel.org/stable/c/1e689a56173827669a35da7cb2a3c78ed5c53680"
        }
      ],
      "title": "smb: server: fix use-after-free in smb2_open()",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-43378",
    "datePublished": "2026-05-08T14:21:27.319Z",
    "dateReserved": "2026-05-01T14:12:56.006Z",
    "dateUpdated": "2026-05-11T22:23:25.827Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}